This Application is related to the subject matter described in the following U.S. patents: U.S. Pat. No. 5,578,813, filed Mar. 2, 1995, issued Nov. 26, 1996, and entitled FREEHAND IMAGE SCANNING DEVICE WHICH COMPENSATES FOR NON-LINEAR MOVEMENT; U.S. Pat. No. 5,644,139, filed Aug. 14, 1996, issued Jul. 1, 1997, and entitled NAVIGATION TECHNIQUE FOR DETECTING MOVEMENT OF NAVIGATION SENSORS RELATIVE TO AN OBJECT; and U.S. Pat. No. 5,786,804, filed Oct. 6, 1995, issued Jul. 28, 1998, and entitled METHOD AND SYSTEM FOR TRACKING ATTITUDE. These three patents describe techniques of tracking position movement. Those techniques are a component in a preferred embodiment described below. Accordingly, U.S. Pat. Nos. 5,578,813, 5,644,139, and 5,786,804 are hereby incorporated herein by reference.
This application is also related to the subject matter described in U.S. Pat. No. 6,057,540, filed Apr. 30, 1998, issued May 2, 2000, and entitled MOUSELESS OPTICAL AND POSITION TRANSLATION TYPE SCREEN POINTER CONTROL FOR A COMPUTER SYSTEM; U.S. Pat. No. 6,151,015, filed Apr. 27, 1998, issued Nov. 21, 2000, and entitled PEN LIKE COMPUTER POINTING DEVICE; and U.S. patent application Ser. No. 09/052,046, filed Mar. 30, 1998, entitled SEEING EYE MOUSE FOR A COMPUTER SYSTEM. These two related patents and patent application describe screen pointing devices, with embodiments that use techniques described in U.S. Pat. Nos. 5,578,813, 5,644,139, and 5,786,804. U.S. Pat. Nos. 6,057,540 and 6,151,015, and U.S. patent application Ser. No. 09/052,046, filed Mar. 30, 1998, entitled SEEING EYE MOUSE FOR A COMPUTER SYSTEM, are hereby incorporated herein by reference.
This invention relates generally to optical sensor devices. This invention relates more particularly to an optical sensor device for sensing relative movement in three dimensions.
The use of a hand operated pointing device for use with a computer and its display has become almost universal. By far the most popular of the various devices is the conventional (mechanical) mouse, used in conjunction with a cooperating mouse pad. Centrally located within the bottom surface of the mouse is a hole through which a portion of the underside of a rubber-surfaced steel ball extends. Interior to the mouse are rollers, or wheels, that contact the ball at its equator and convert its rotation into electrical signals representing orthogonal components of mouse motion. These electrical signals are coupled to a computer, where software responds to the signals to change by a xcex94X and a xcex94Y the displayed position of a pointer (cursor) in accordance with movement of the mouse.
In addition to mechanical types of pointing devices, such as a conventional mouse, optical pointing devices have also been developed, such as those described in the incorporated patents and patent application. In one form of an optical pointing device, rather than using a moving mechanical element like a ball in a conventional mouse, absolute movement between an imaging surface, such as a finger or a desktop, and photo detectors within the optical pointing device, is optically sensed and converted into movement information.
The photo detectors in optical pointing devices are typically implemented in a flat, two-dimensional array. The array of photo detectors is capable of measuring absolute two-dimensional movement. As the array moves across an image, or the image moves across a stationary array, motion can be detected by comparing successive images. The sensed motion is in terms of the number of pixels that the image on the pixel array has moved. The array is at a fixed distance and a fixed angle from the surface being imaged, so the motion that is sensed is absolute (within the error tolerance of the system). The surface or scene that is imaged by an optical pointing device is a near-field image, meaning that the surface is very close to the sensor array.
If optics are used that allow the sensor array to focus on far-field objects, then the distance to the objects is not known and the sensed movement is relative. It would be desirable to provide a three-dimensional relative movement sensing apparatus using multiple conventional two-dimensional photo detector arrays and appropriate optics for focusing far-field objects.
One form of the present invention provides an apparatus for sensing three-dimensional relative movement. The apparatus includes a movable motion sensor including a first and a second two-dimensional array of photo detectors. At least one lens directs far-field images onto the first and the second arrays of photo detectors. The sensor is configured to generate digital representations of the far-field images and to generate three-dimensional relative movement data based on the digital representations of the far-field images. The movement data is indicative of motion of the sensor in three dimensions.